A total of 320 subjects with type 1 diabetes will be randomized across approximately 40 centers in the six-month comparative trial. Approximately 15 centers will recruit pediatric subjects only (ages 12-17 years), the other sites will recruit only subjects age 18 to 65 years. Half will receive an inhaled insulin regimen and half a conventional subcutaneous insulin regimen. All who successfully complete the six-month trial will be eligible for participation in a long-term open-label extension of inhaled insulin therapy.